I sliced the 4500K 519A that came with the NLightD E1 that I won in the 12th Annual Old Lumens Challenge. Domed, the LED was slightly rosy, but still a little boring to me. So I sliced it down 1.25mm and I think it looks so much better, including the beam.
When I first put the head back together, there was a gap between the bezel and the head, so I screwed it on even tighter to the point where the O-ring started to bulge. Then I realized the O-ring needed to be put in the groove on top of the reflector and underneath the lens rather than on top. 
